Automatic hinge-mounted door closer



July 7, 1970 wE|NER 3,518,715

AUTOMATIC HINGE-MOUNTED DOOR CLOSER Filed Jan. 24, 1968 4 2 Sheets-Sheet1 M/CHDEL M. WE/NEQ 5L L INVENTOR.

MWZM p Q SEY United States Patent 0 3,518,715 AUTOMATIC HINGE-MOUNTEDDOOR CLOSER Michael M. Weiner, Los Angeles, Calif. (P.0. Box 36,Woodland Hills. Calif. 913-64) Filed Jan. 24, 1968, Ser. No. 700,061

Int. Cl. 7505f 1/08 US. Cl. 16--80 l2 Germs ABSTRACT OF THE DISCLOSUREAn automatic door closer mountable directly on a door hinge by means ofthe door hinge pin only. A stationary arm abuts against the door frame.A rotatable arm abuts against the door and pivots with the door aboutthe pivotal axis of the door hinge, i.e., the hinge pm axis. A spring isinterconnected between the stationary and rotatable arms in asubstantially constant torque arrangement whereby a constant restoringtorque is applied by the spring about the hinge pin for closing the doorafter opening thereof. A latch is provided for deactivating the device.Geometrical, trigonometrical and mathematical relationships and designparameters are disclosed.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates to an automatic closing device for a hinge-mounted door and,more particularly, to such a device for mounting directly on the hingesolely via the hinge pin, exerting a substantially constant reactiveforce against door opening forces, and providing a substantiallyconstant restoring force for closing the door automatically andcompletely without slamming.

Description of the prior art Although a number of automatic door closingmechanisms exist in the prior art, such mechanisms are usually bulky andcomplicated devices primarily intended for installation on heavyexternal doors. Their installation on doors connecting interior roomswould involve considerable expense, difliculty in installation andpermanent marring of the door and door frame surfaces duringinstallation and use. Furthermore, their conspicuousness would seriouslydetract from the normal interior decor.

Some devices of the prior art employ either extension, compression ortorsion springs which are conventional in operation during the dooropening operation to generate restoring forces. Due to the fact thatHooks law dictates the result in such devices that the restoring torqueis linearly proportional to the door opening angle, such devices sulferfrom the disadvantages of excessive or slamming force exerted on thedoor if opened fully and yet insufficiently slight restoring torque ifthe door is opened slightly. In an attempt to overcome thesedisadvantages, pneumatic cylinder-piston damping mechanisms have beenemployed in conjunction with such springs so that higher spring forcescan be used. However, due to the normal necessity of a bleeder port inthe cylinder, such combinations are still dependent on the speed andextent of the door opening action, are somewhat critical in adjustmentand maintenance, are expensive and bulky, require permanent installationalbeit removable for repairs, and still often do not provide sufficientrestoring forces for closing the door completely to overcome theresistance of the door knob mechanism when the door has been opened onlyslightly.

SUMMARY OF THE INVENTION According to the present invention, theforegoing probice lems of the prior art mechanisms have been eliminatedby providing a simple but effective automatic door closer device whichemploys an arrangement comprising a substantially constant force springhaving one end immobilized relative to the stationary door frame and theother end immobilized relative to the movable door whereby the springarrangement exerts a substantially constant restoring torque atsubstantially all degrees of door opening action but provides arelatively high restoring torque at initial or small degrees of dooropening angles suflicient to overcome the resistance of the door knobmechanism and effect smooth door closure with little or no slammingaction. Further, the respective spring ends are mounted on a pair ofarms which respectively abut against the door frame and the door, sucharms being mounted on the door hinge solely by means of the door hingepin, thus eliminating any marring of the door and door frame surfaceswhile achieving ease of installation and removal. Still further, thearrangement of the spring and arms is such as to create a moment armwhich varies slightly in magnitude oppositely to the slight variationsin spring force over the practical range of door opening angles wherebythe restoring torque (the product of the moment arm and the springforce) is effectively constant over such range. Additionally, a latch isprovided for selective manual deactivation of the device wheneverdesired, without disabling or otherwise interfering with either the dooror the mounting of the device.

Accordingly, it is an object of the present invention to provide a noveldevice for automatically closing a door.

Another object of the present invention is to provide an automatic doorcloser which is easy to install and remove without marring of the doorand door frame surfaces.

Another object of the present invention is to provide a hinge-mounteddoor with an automatic door closer which is operatively mounted on thedoor hinge solely by means of the door hinge pin.

A further object of the present invention is the provision of anautomatic door closer which applies a substantially constant doorclosing torque over a wide range of door opening angles.

A further object of the present invention is the provision of anautomatic door closer which applies a substantially constant but lowtorque for closing the door over a wide range of door opening angles andalso applies a relatively increased closing torque for very small dooropening angles for overcoming the resistance of the door knob mechanism.

A further object of the present invention is the provision of anautomatic door closer with a simple latch means to disconnect the devicefrom use without physically removing it or interfering with normal doorfunctrons.

Still further objects of the present invention include the provision ofan automatic door closer which is simple and inexpensive to manufacture,small in size and inconspicuous in location, readily installed andremoved without requiring the exercise of skill or the use of tools,readily installed on a wide range of different types of doors, reliablein use, requires little or no maintenance or repair, readily packagedand marketed, and attractive 1n appearance.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. The presentinvention, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may best be understood byreference to the following description of a preferred embodiment, takenin connection with the accompanying drawings.

3 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a reduced size perspectiveview of a hingemounted door closer in accordance with the presentinvention, shown mounted on a door hinge in operative association with adoor and door frame;

FIG. 2 is a fragmentary elevational view thereof taken substantiallyalong line 2-2 in FIG. 1;

FIG. 3 is a top plan view thereof with the aspect taken along line 33 inFIG. 1, with the door in a closed position;

FIG. 4 is a top plan view thereof with the door in an open position;

FIG. 5 is an elevational view thereof in the closed door position, withthe spring being broken away for clarity of illustration of the otherelements;

FIG. 6 is an exploded perspective view, similar in aspect to FIG. 1,showing the stationary and rotatable arms, the pin for mounting a springend to the stationary arm, and the latch;

FIG. 7 is an enlarged sectional view taken substantially along line 7-7in FIG. 5, with the door hinge pin shown in broken lines; and

FIG. 8 is a graph illustrating the restoring torque characteristics ofthe illustrated device.

DESCRIPTION OF A PREFERRED EMBODIMENT It should be noted that FIGS. 3-5inclusive are full scale drawings of a preferred embodiment of thepresent invention having optimum performance characteristics. As shouldbe clear, however, the structural dimensions, proportionalrelationships, and spacings between structural and functional pointswhich vary due to relative motion therebetween may be varied withoutdeparting from the inventive concepts disclosed herein and particularlyto accommodate differing environmental parameters from those disclosedherein in connection with the particular interior household doorapplication for which the disclosed preferred embodiment has particularand novel utility.

Referring to the drawings, and particularly to FIGS. 1 and 2 initially,there is seen an automatic hinge-mounted door closer 10 in accordancewith the present invention mounted on a conventional door hinge 12, theplates 14 and 16 of which are conventionally secured to a doorjamb 18 ofa wall 19 and a door 20. The door closer 10 is seen to comprisegenerally first and second arm members 22 and 24, one end or portion ofeach of which is mounted on the door hinge 12 in pivotal relationship toeach other via door hinge pin 26. A spring 28 is secured at its oppositeends to the respective arm members 22 and 24. A latch 30 is mounted onarm member 22. Arm members 22 and 24 are provided with respectiveresilient pads 32 and 34 for abutment against the door and conventionaldoor frame molding 36, respectively.

Referring more particularly now to FIGS. 3-7, it is seen that armmembers 22 and 24 are each of unitary construction and may be cast orformed to integrally provide a plurality of strengthening ribs alongtheir lengths, such as are indicated at 38 and 40, respectively. Armmember 22 is integrally provided with a pair of vertically alignedspaced collars 42 and 44 defining a horizontal slot 46 therebetween forfreely receiving an end 48 of spring 28 therein. Collars 42 and 44 areprovided with a common vertical hole 50 therethrough for receiving a pin52 therein, the pin 52 having an enlarged head 54 to prevent the pin 52from dropping through the hole 50. The spring end 48 is looped about thepin 52 so that the spring end 48 is removably captured by pin 52 and maypivot thereabout. The free end of arm member 22 is provided with a fiatvertical surface 56 upon which resilient pad 32 is secured, as by glueor adhesive, it being understood that pads 32 and 34 of the device areprovided merely for the purpose of preventing marring or scratching ofthe surfaces against which they rest and 4 may be composed of neoprene,felt or similar suitable materials.

The adjacent ends, indicated generally at 58 and 60, of

arm members 22 and 24, respectively, are integrally provided withrespective sleeves 62 and 64 which receive a bushing 66 commontherethrough, preferably with a washer 68 between the sleeves 62 and 64to assure relative rotation freely therebetween. Bushing 66 preferablyis crimped or upset at its opposite ends 70 and 72 to retain the sleeves62 and 64 thereon in a unitary manner. Bushing 66 is adapted to receivethe door hinge pin 26 therethrough, with its enlarged head 74 resting onthe bushing end 70. It may be noted that the clearances between thevarious elements particularly shown in FIG. 7 are not critical, it beingdesirable merely that hinge pin 26 can be freely slipped through bushing66 and that sleeve 62 may be freely rotatable relative to sleeve 64.Thus, a journal relationship between the bushing 66 and sleeve 62 of armmember 22 is sufficient to assure such function. It also should be notedthat the structural couplings illustrated in FIG. 7 constitute the solestructural support for the inventive automatic door closer deviceillustrated here- The stationary arm member 24 has a substantiallyV-shaped configuration to form an elbow region, indicated generally at76, integrally provided with a collar 78 having a vertical hole 80therein for loosely receiving a pin 82 therethrough. The pin 82 (bestseen in FIGS. 5 and 6) has an enlarged head 84 for ease in manualgripping during assembly and disassembly of the device and is preferablyprovided with a pair of vertically spaced annular projections 86 and 88which define an annular slot 90 therebetween for loosely receiving theother end 92 of the spring 28. The spring end 92 is looped about andthus captured by the pin 82. As in the case of the spring end 48, springend 92 may be merely free to pivotally rotate about the longitudinalaxis of its capturing pin 82 and, thus, if pin 82 is freely rotatablewithin its collar 78, spring end 92 may be either tight or loose aboutpin 82.

Referring now more particularly to FIGS. 3 and 4, it is seen that thespring 28, in and of itself, is a conventional coil spring having aplurality of identical coil portions which, in their substantiallyrelaxed state as indicated at 28 in FIG. 3, form an effectivelycylindrical configuration in gross. Spring ends 48 and 92 are formedfrom continuous extensions of the coils 28 at the ends of the cylindervia respective end portions and 102. It should be noted that animaginary line, indicated at 103, drawn between the axes of rotation ofspring ends 48 and 92, i.e., the longitudinal axes of pins 52. and 82,respectively, falls outside the effectively cylindrical exterior of thebody of the spring 28.

As seen in FIG. 4, opening of the door 20 causes rotatable arm 22 topivotally rotate about the vertical axis, indicated at 104, of the doorhinge pin 26 so that the vertical axis, indicated at 106, of pin 52describes an are about hinge pin axis 104, thus bringing spring end 52closer to spring end 92 which, as previously mentioned, has the pivotalaxis indicated at 108 which is the longitudinal axis of pin 82 and isspaced from hinge pin axis 104. The spring 28 is deflected into a curvedarc, FIG. 4 illustrating the spring 28 in a fully deflected positionafter the door 20, and, accordingly, rotating arm member 22 have beenrotated to an angle of 100.

At the position shown in FIG. 4, the latch 30 can be secured about pin82, preferably at the exposed shank portion 110 (see FIGS. 5 and 6)whereby the arms 22 and 24 are locked together. Note the simplicity oflatch 30, which is merely fastened to rotating arm member 22 at 112 asby a machine screw so that the hooked end 114 is firmly held in lockingengagement with the pin 82 by virtue of the restoring force of thespring 28 which otherwise would cause removal of arm member 22 from itsposition adjacent the pin 82. It should be noted that rotating armmember 22 is not attached or in any manner secured to door 20, so thatthe door 20 is free to rotate about its hinge pin 26 withoutinterference from the thus-latched device all the way from the closeddoor position of FIG. 3 to the 100 open position of FIG. 4.

As now should be clear, if the latch 30 is not engaged as abovedescribed, the spring 28 exerts a force on the rotating arm member 22which, in turn, exerts a restoring torque on the door 20 forcing thedoor to close and return to the position shown in FIG. 3. The restoringtorque provided by the device is the product of the force exerted by thespring 28, which acts along the line 103 joining the axes or centers ofthe restraining pins 52 and 82, and a moment arm which is the distancefrom the axis 104 of the hinge pin 2.6 to the line 103 of force. FIG. 8is a graph illustrating the foregoing relationships in a qualitativemanner. Thus, curve 120 shows the variations in the above-describedmoment arm with a door opening angle varying from closed to the openposition of FIG. 4 (100), curve 122 shows the varying force of spring 28exerted along the line 103 of force, and curve 124 is a plot of theproducts of the respective distances and forces of curves 120 and 122for the various door opening angles; thus, curve 124 is a plot of therestoring torque exerted by the above-described automatic door closer10. It should be noted that the restoring torque is revealed by curve124 to be nearly uniform for a wide range (indicated at 126) of dooropening angles, approximately 10 to 70. Importantly, it should also benoted that a rapid, though not excessive, rise in the restoring torqueis obtained at very small door opening angles of 0 to about 5 (indicatedat 128), thus achieving the highly advantageous effect of firm doorclosing without excessive slamming action.

It now should be clear that the performance characteristics of anyparticular device made in accordance with the present invention aredependent only on the particular values chosen for the parametriclengths of arms 22 and 24 and the angle included therebetween, assumingpredetermined values and dimensions of the spring 28. Accordingly, thefollowing discussion refers to FIGS. 3 and 4 for clarity and willestablish the appropriate criteria and relationships therefor so thatthe performance under static conditions (torque vs. opening angle)illustrated in FIG. 8 can be calculated.

The static torque exerted by the device is experienced equally by arms22 and 24, although in opposite directions, and can be expressed interms of the effective lengths of the arms 22 and 24, the angle includedthere between, and the force exerted by spring 28. The effective lengthof arm 22 is the distance between points 104 and 106, which arm lengthwill be referred to herein as L similarly, the effective length of arm24 is the distance between points 104 and 108, referred to herein as LThe included angle between the effective geometrical arms L and L willbe referred to as Y. The force exerted by the spring 28 along its lineof action 103 will be referred to as P, and the length of line 103between points 106 and 108 will be referred to as L The static torque Tis the product of the force P exerted by the spring 28 and a moment armequal to the perpendicular distance from point 104 to the line 103. Fromtrigonometry, it follows that the torue T and length of line L are givenby the following expressions:

The force P exerted by the spring is dependent on the spring design. Forthe particular optimum spring 28 illustrated, the force P and springdeflection S (the increment of change in length of line L are calculatedby the following expressions:

P=applied force (1b.)

d=wire diameter (in.) Dzmean coil diameter (in.) S =spring deflection(in.) P initial tension (1b.)

Rzarm angle (degrees) N=number of active coils 28' Q=spring body angle(radians) G=torsional modulus (p.s.i.) A=arm length (in.)

The arm length A is the effective length of the spring end portion or102 and is measured between the extremus of the last active coil 28 andthe springs adjacent pivot point 106 or 108. The arm angle R relates tothe angular relationship of the spring body and its connecting endportions to the pivot points 106 and 108, and constitutes the acuteangle included between two lines drawn in the closed door position ofFIG. 3, one of which lines is an extension of an axial line tangent tothe mean coil periphery, the other of which lines is from the adjacentpivot point 106 or 108 to the closest point of the last active coil 28'.It should be noted that the spring force P is not given explicitly interms of the deflection S but that both force P and deflection S aregiven in terms of another parameter called the body angle Q which,viewing FIG. 4, is the acute angle included between a line transverselybisecting the spring 28 and, therefore, normal to a line 103 betweenpivot points 106 ad 108, and a line through one of the pivot points 106or 108 and lying in the mean plane of the opposite (most remote) activecoil 28.

The optimum values for the parameters of the short arm L the long arm Land the angle Y included therebetween have been computed and haveresulted in the full scale configuration illustrated. However, theforegoing disclosure will enable anyone having ordinary skill in the artto modify any and all of the parametric values to achieve desiredperformance characteristics under the same or different environmentalconditions of any particular application.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from thisinvention in its broader aspects, and, therefore, the aim in theappended claims is to cover all such changes and modifications as fallwithin the true spirit and scope of this invention.

I claim: 1. An automatic door closer adapted for mounting on theconventional hinge of a door via the hinge pin only and adjacent thedoor frame, comprising:

stationary arm means having a first portion mountable on the door hingevia the door hinge pin and a second portion adapted to abut against thedoor frame;

rotatable arm means having a first portion pivotally mountable on thedoor hinge via the door hinge pin and a second portion adapted to abutagainst the door whereby opening rotation of the door about its hingepin will cause pivotal rotation of said rotatable arm means about thedoor hinge pin;

spring means having first and second ends each pivotally connected to arespective one of said stationary and rotatable arm means at arespective location spaced from the door hinge pin whereby such pivotalrotation of said rotatable arm means causes deflection of said springmeans to generate a restoring torque operable upon said rotatable armmeans in a door closing direction; and

a latch mounted on one of said arm means in selectively releasablyretainable engagement with the other of said arm means when said armmeans are juxtaposed relative to each other.

2. An automatic door closer adapted for mounting on the conventionalhinge of a door via the hinge pin only and adjacent the door frame,comprising:

stationary arm means having a first portion mountable on the door hingevia the door hinge pin and a second portion adapted to abut against thedoor frame; rotatable arm means having a first portion pivotallymountable on the door hinge via the door hinge pin and a second portionadapted to abut against the door whereby opening rotation of the doorabout its hinge pin will cause pivotal rotation of said rotatable armmeans about the door hinge pin;

spring means having first and second ends each connected to a respectiveone of said stationary and rotatable arm means at a respective locationspaced from the door hinge pin whereby such pivotal rotation of saidrotatable arm means causes deflection of said spring means to generate arestoring torque operable upon said rotatable arm means in a doorclosing direction; and

said spring means end locations are spaced at different distances fromthe door hinge pin whereby, as said rotatable arm means pivotallyrotates about the door hinge pin, the line of force exerted by saidspring means between said locations pivots about said location of saidstationary arm means for varying the moment arm of said restoringtorque.

3. A closer as defined in claim 2 wherein said spring means comprises asubstantially constant force spring.

4. A closer as defined in claim 3 wherein said spring is a coil spring.

5. A closer as defined in claim 2 wherein said spring means comprises acoil spring, such connections of said first and second ends are pivotalconnections, and said spring includes a coil body having opposite endarms respectively provided with said first and second ends and angularlyprojecting from said coil body whereby said coil body resides to oneside of and parallel to said line of force when said spring is in itsnormal undefiected position and said coil body deflects arcuately awayfrom said line of force during door opening rotation of said rotatablearm means.

6. A closer as defined in claim 5 further comprising:

a latch mounted on one of said arm means in selectively releasablyretainable engagement with the other of said arm means when said armmeans are juxtaposed relative to each other.

7. A closer as defined in claim 5 wherein such distance from the doorhinge pin is greater for said rotatable arm means than such distance forsaid stationary arm means.

8. A closer as defined in claim 7 further comprising:-

a latch mounted on said rotatable arm means in selectively releasablyretainable engagement with said stationary arm means when said arm meansare juxtaposed relative to each other.

9. An automatic door closer adapted for closing a conventional doorwhich is mounted on a door frame via a hinge and is rotatable about thehinge pin, comprising:

stationary arm means mountable on the hinge pin and adapted to beimmobilized relative to the door frame with a first portion located afirst distance from the hinge pin;

rotatable arm-means pivotally mountable on the hinge pin with a secondportion located a second distance from the hinge pin and adapted to beimmobilized relative to the door for rotation therewith about the hingepin;

spring means having first and second ends pivotally connected to saidfirst and second portions respectively whereby such rotation of saidrotatable arm means causes deflection of said spring means; and

latch means mounted on one of said arm means in selectively releasablyretainable engagement with the other of said arm means when said armmeans are juxtaposed relative to each other.

10. An automatic door closer adapted for closing a conventional doorwhich is mounted on a door frame via a hinge and is rotatable about thehinge pin, comprising:

stationary arm means mountable on the hinge pin and adapted to beimmobilized relative to the door frame with a first portion located afirst distance from the hinge pin;

rotatable arm means pivotally mountable on the hinge pin with a secondportion located a second distance from the hinge pin and adapted to beimmobilized relative to the door for rotation therewith about the hingepin, said first and second distances being unequal; and

a substantially constant force coil spring having first and second endsconnected to said first and second portions respectively whereby suchrotation of said rotatable arm means causes deflection of said spring inan arc, and initial deflection of said spring is more forceful thansubsequent deflection for relatively greater door closing force at smalldoor opening angles.

11. A closer as defined in claim 10 wherein said second distance isgreater than said first distance.

12. A closer as defined in claim 11 further comprising:

latch means mounted on one of said arm means in selectively releasablyretainable engagement with the other of said arm means when said armmeans are juxtaposed relative to each other.

References Cited UNITED STATES PATENTS 50,239 10/1865 Gerard l6l461,034,971 8/1912 Brown et a1 l6l46 270,368 l/1883 Barlow 16-76 1,147,8277/1915 Tanner 16-190 3,157,906 11/1964 Wolf 16-50 3,329,991 7/1967Gobble l650 BOBBY R. GAY, Primary Examiner R. D. KRAUS, AssistantExaminer

